1. Technical Field
The present invention relates to an interference filter, an optical filter device, an optical module, and an electronic apparatus.
2. Related Art
A known interference filter has a pair of reflecting films opposed to each other and a gap dimension between the reflecting films is varied to thereby take out light having a predetermined wavelength (see, e.g., JP-A-2002-277758).
In the interference filter described in JP-A-2002-277758, a pair of reflecting films are disposed respectively on surfaces of two optical substrates opposed to each other, and a capacitance electrode is disposed on an outer side of the reflecting film of each of the optical substrates.
Incidentally, in the interference filter described in JP-A-2002-277758, a metal film and a dielectric multilayer film are recited as examples of the reflecting film. Here, in the case of using the dielectric multilayer film as the reflecting film, generally, a lift-off pattern is provided to the optical substrate, then the dielectric multilayer film is formed, and then lift-off is performed to thereby form the reflecting film at a predetermined position of the optical substrate.
However, in the case of forming the dielectric multilayer film using such a lift-off process, since it is necessary to perform the process of forming the lift-off pattern and the lift-off process, there is a problem that the production efficiency is degraded. Further, the side surface (end surface) of the dielectric multilayer film formed by the lift-off process becomes perpendicular to an upper surface corresponding to the optical substrate. On this occasion, in the case of, for example, providing the reflecting film with the electrode, and forming a leader line of the electrode to the outer peripheral portion of the optical substrate, there also occurs a risk that the leader line is broken on the end surface of the dielectric multilayer film.